1. Field of the Invention
The present invention relates to a plasma display panel (PDP), and more particularly, to the arrangement of barrier ribs of a PDP to form both open and closed discharge cells.
2. Description of the Related Art
PDPs are emerging as one of the most popular flat panel display configurations used for wall-mounted televisions and other similar large-screen display applications. Predetermined images are displayed on the PDP using a discharge mechanism of discharge cells. In more detail, the PDP combines two substrates on which a plurality of electrodes is formed to realize a vacuum assembly, and discharge gas is provided between the two substrates before sealing the same. Discharge voltages are applied to the electrodes to thereby effect plasma discharge, and ultraviolet rays generated during discharge excite phosphors formed in a predetermined pattern to thereby realize the display of desired numbers, characters, and/or graphics.
PDPs are classified into two different discharge types, namely, a DC PDP and an AC PDP, depending on the drive voltage waveform. PDPs can also be classified into either an opposing discharge PDP or a surface discharge PDP, depending on the electrode structure.
Discharge cells are defined by barrier ribs formed in a predetermined pattern (for example, a stripe pattern or a lattice pattern) on one of the substrates. The barrier ribs act to separate the discharge cells corresponding to a pixel pattern and also function as a spacer to maintain a cell gap between the two substrates.
The different formations of the barrier ribs have different advantages. In particular, with the use of stripe barrier ribs, the many discharge cells present between the barrier ribs are in communication (i.e., the discharge cells between each pair of adjacent barrier ribs are in communication), and as a result, exhaust of the PDP and sealing of the discharge gas within the PDP are relatively easily performed during manufacture.
With closed barrier ribs realized by a lattice pattern of the same, on the other hand, the discharge cells are not in communication. That is, the barrier ribs are formed into individual units having a quadrilateral, hexagonal, or other such shape. With the closed barrier ribs, the discharge cells are separately formed for each pixel, and phosphors can be deposited over all inner surfaces of barrier ribs that form each pixel. Therefore, an area of illumination for each unit pixel is increased by increasing the amount of space on which phosphors can be deposited. The result is an increased brightness of the PDP.
This advantage of the lattice barrier rib structure has led to greater application of the same over the stripe configuration in recent times.
However, the barrier ribs provided in a lattice pattern make exhaust of the PDP difficult during manufacture. In more detail, depressions are typically formed on distal ends of the barrier ribs such that gaps are formed between the barrier ribs and an element of the substrate opposing the substrate on which the barrier ribs are formed, for example, an MgO oxidation layer. Although these gaps form exhaust paths to allow evacuation of the PDP, the minimal size of the gaps is such that there is significant resistance during this process. Japanese Laid-Open Patent No. 2002-175762 relates to a PDP with this structure.
A different configuration is introduced in Japanese Laid-Open Patent No. Heisei 2002-83545 which relates to a PDP where closed barrier ribs are formed using a material that has a heat shrink property. The barrier ribs are formed having areas of a lesser height that function as exhaust paths to thereby form a mesh-type structure of the exhaust paths. Although it is claimed that such a barrier rib structure reduces exhaust resistance during the evacuation process, there is a limited number of actual paths through which exhaust can occur as a result of the mesh configuration. This can result in insufficient exhaust of the PDP.
The following patents each discloses features in common with the present invention but do not teach or suggest the inventive features specifically recited in the present application: Japanese Patent Publication No.2002-175762 to Ueda, entitled PLASMA DISPLAY PANEL AND ITS MANUFACTURING METHOD, published on Jun. 21, 2002, and Japanese Patent Publication No. 2002-83545 to Kunii, et al., entitled PLASMA DISPLAY PANEL AND METHOD FOR MANUFACTURING THE SAME, published on Mar. 22, 2002.